Conventionally, in a case of a telephone call, the telephone call is received in response to a connection request from a caller. For a case in which a line is set to a hold state in order to respond to an inquiry, a request, and the like from a caller, there are various approaches to release the hold state by a held side.
A technology is presented in that a special number is dialed at a held side to send a hold release request signal or the like, and a speaker of a telephone at a holding side is turned on to communicate with a person with voice at the holding side. A technology is presented in that a message recorded by the held side is corresponded to a telephone number of the holding side. A technology is presented to recover a communication state by releasing the hold state when a re-connection is available within a predetermined time after a call is set to the hold state in response to the communication state or a remaining battery level of a wireless communication terminal. A technology is also presented to record a telephone number of the held side when a connection is disconnected at the held side during the hold state and to re-connect from the hold side.